Resumen de Respiration, microbial biomass and nutrient availability are influenced by previous and current soil water content in plant residue amended soil
Yanchen Zhang, Petra Marschner
The aim of this study was to determine how soil respiration, microbial biomass and nutrient availability after the first and second plant residue addition are influenced by soil water content and number of days between rewetting of dry soil and second residue addition. A loamy soil was amended with low C/N ratio (L) or high C/N ratio (H) plant residues and then maintained at 10% or 50% water holding capacity (WHC) for 10 days after which the soil at 10% WHC was rapidly rewetted to 50% WHC. A second residue with a different C/N ratio than the first was added one, two or five days after rewetting. Lower water content (10% WHC) during the first 10 days reduced respiration and microbial biomass. After day 10, MBN increased with number of days after rewetting. After the second residue addition, respiration rate in the first three to four days and available N after two days were higher when residue was added five days after rewetting compared to one day. But MBN was higher in treatments with residues added one day after rewetting compared to amendment after five days. The water content in the first 10 days had little effect on microbial biomass and nutrient availability after the second residue addition. We conclude that soil respiration, N mineralisation and immobilisation are influenced by the interval between plant residue additions, particularly in rewet soil.
